Hob-grinding machine



C. G. OLSON AND F. W. ENGLAND.

HOB GRHVDING MACHINE. APPLICATION mm r55. 7. I919 Patented July 5, 1921.

4 SHEETS-SHEET l c. a. OLSON AND F. w. ENGLAND.

HOBGBINDING MACHINE. APPLICATIQON FILED m1. 7, 1939.

Md W? W m Q m m a C. G, OLSON AND F. W. ENGLAND.

HOB GRINDING MACHINE.

APPLICATION FILED ma. 7, IBM).

c. e. OLSON AND r. w. ENGLAND. H08 sn'mome MACHINE.

APPLICATION FILED FEB. 7| I9I9.

1,383,843. Patented July 5, 1921,

4 SHEETS-SHEET 4- ing machines and similar machines in which ,UNITED STATES PATENT OFFICE.

CARL G. OLSON AND FRANK W. ENGLAND, OF CHICAGO, ILLINOIS, ASSIGNORS TO ILLINOIS TOOL WORKS, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

HOB-GRINDING MACHINE.

,ipeclflcation of Letters Patent.

Application .flled February 7, 1919. Serial No. 275,537.

FRANK W. ENGLAND, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois-have invented a certain new and useful Improvement in Hob-Grinding Machines, of which the following is a specification Our invention relatcsto machine tools, and is particularly applicable to hob grindit is required that there be frequent relative movement between the tool and work in a, radial direction,-that is, toward and .from the axis of the work. In the accompanying drawings we have shown a grinding wheel acting upon the teeth of a hob. The grinding tool revolves about a stationary axis and the wwhine is so constructed as to move the h toward and from the work for producing the necessary relief upon the rob. The work holder swings the hob toward and from the grinding wheel and this movement is effected by a rotating cam. Special means are provided for transmitting the throw of the cam to the work holder and advantageous means are provided for altering the throw of the work holder without changing camsu Meansare also provided for reversing the position of the tool relatively to the work. In our illustrated ma chine, also, the grinding tool is located behind the work,that is, on the side bpposite to the operator. Furthermore, the parts are so arranged and operated that the grinding tool moves downward at the point of contact with the work, with the result that the sparks are driven downward instead of upward and it becomes safe for the operator to bring his face close enough to the acting point to scrutinize the progress of the work. The object of our invention is to produce a machine having the foregoing characteristics and to produce the various combinations and sub-combinations by which the results ma be obtained.

o explain the invention we have chosen to illustrate it in a form adapted for the grind ing of hobs, and in the accompanying draw- Tigure 1 is a front elevation partly in sectionmf the complete machine.

Fig. 2 is an and elevation looking toward the left in Fig. 1.

Fig. 3 is'a top plan view of the hob, tool, and tool holder.

Fig. 4 is an elevation of the change gears as viewed when looking in the direction of the arrow A, Fig. 1.

Fig. 5 is a view, more or less diagrammatic, showing the work holder, its support,

and the cam mechanism which :u-tnates it.

Fig. 6 is a perspective view showing some of the more essential portions of the ma chine, so far as our invention is concerned, and

Fi Tis a veitical sectional view on the line -7, Fig. l. Like numerals denote like parts throughout the several views. In the form selected to illustrate the invention, the machine has a main frame'or bed 1 on which a table 2 is longitudinally slidable. A table 3 is transversely slidable upon table 2 and carries near the rear end a post 4-. A tool holding frame or tool carrier 5 is pivoted to the upper end of post 4 means of a pin 6 or equivalent device. In said frame there is journaled a spindle 7, shown in dotted lines in Fig. 3. Said spindle is adapted to take the arbor 8 of the grinding tool 9. The spindle is driven by a pulley 10 which, in turn, is driven by a belt 11. The belt is driven by a pulley 12 journaled in a yoke 13 which is slidably mounted on frame 5 so as to enable it to move toward and from the pulley It). A helical gonipression spring 14 tends to force the'pnlleys apart and thus keep the belt tights Pulley 12 is driven by a sheave l6 fastened to the same shaft 17 as supports the pulle 12. Power to drive the sheave is derived rom a belt 18 driven from a suitable power device overhead (not shown). The hob 20, which constitutes the work in the present case, is mounted on the work arbor 21 and it will be noted that the axis of the tool arbor and spindle is inclined relatively to the axis of the work spindle. This is to compensate for the helical axis ofthe hob. But the in (i which forms a pivot for the tool carrying frame 5 is arranged approximately at right angles to the axis of the arbor 21, and consequently by throwing the frame over,-that is, rotating it about its axis, the position of the grinding wheel will be reversed, thus enabling the wheel to act upon the oppositeside of the hob teeth.

Patented July 5. 1921.

The work arbor 21, above mentioned, is connected to and sup orted and driven by the work spindle 24, )est shown in Fig. 1. Said spindle has a lead screw 25 at the outer end which works in a nut 26,'supported in a cap 27 screwing onto the end of the housing 28. The housing, cap, and nut are stationany so far as longitudinal movement is concerned, and hence as the spindle rotates the work will be advanced longitudinally. In order to kee) the lead screw and nut dust proof, it is desirable to place a cap 30 over the outer end of the screw. According to the present design the cap is fastened to and su ported by the nut.

he work spindle and associated parts are carried at the upper end of a rocking frame which is shown in perspective in Fig. 6. and more or less diagrammatically in Fig. 5. This frame is fulcrumed upon a shaft 33 and consists chiefly of the two arms 35, 36 connected by a cross brace 37. At the u per ends the arms 35, 36 have pillow blocks 39 provided with caps 40. These blocks and caps constitute journal bearings for the otating parts. In the bearing at the left, best shown in Fig. 1, a sleeve 42 is inserted and this. encircles and supports the spindle 24. The sleeve has a collar 43 which abuts one end of the cap, and a screw collar 44 which abuts the other end of the cap and holds the sleeve against longitudinal movement. In the particular form shown, the housing 28 is fastened by screws or-otherwise to the blocks 39 and cap 40 at the left, although it will be understood that the actual design of these parts may be considerably varied without varying the essential principle,- which is that spindle 24 rotates and feeds longitudinally in a rocking frame which, in rocking produces a relative movement between thu work and the tool in a direction transverse to the axis of the work.

The mechanism for rotating the .spindle and at the same time permitting it to feed longitudinally includes arotatable sleeve 46 which is journaled at one end upon the sleeve 42 and has an internal feather 47 which projects into a slot 48 formed in acollar 49 fastened to or forming an integral part of spindle 24, as shown in detail 111 Fig. 7. Said feather extends parallel to the spindle axis and hence drives the spindie but at the same time permits it to travel longitudinally. Sleeve 48 is driven in the present instance by a spur gear 50, driven y a pinion 51 fastened to the shaft 33, above mentioned. Said shaftis journalcd in bearings 53, 53, rising from the stationary bed 1 and is driven by a pulley 54. as best shown in Fig. 1. In practice said pulley is not ri idly fastened to the shaft, but is connecte to it through reversing transmission mechanism adapted to drive the shaft at a relativelyslow speed forward. and relatively high speed backward. Reversible transmissions suitable for the purpose are well known and consequently need not be here described in detail. Pulley 54 is driven by a belt 55 from a suitable overhead power device (not shown).

Now referring particularly to the mechanism which oscillates the rocking frame 35, 36, 37: A cam shaft 57 is journaled in stationary bearings 58, 58 and is driven by change gears from the shaft 33. As shown in perspective in Fig. 6 and in detail in Fig. 4, a gear wheel 60 is fastened to shaft 33, a gear wheel 61 is fastened to shaft 57. and motion is transmitted from one to the other by intermediate gears 62, 63 which rotate as a single piece and mesh respectively with the wheelsGO and (51. These intermediate gears are supported upon a'stud 64 adapted to be clamped in any suitable position upon a slotted arm 65 pivoted to shaft 57. By suitably selecting the intermediate pinions 62, 63 any desired speed ratio between shafts 33 and 57 may be obtained. Although it is not essential, it is desirable to form the cam shaft in two parts 57, 57 connected by a spring ratchet mechanism 68 shown in perspective in Fi 6. The function of the ratchet mechanism is to permit the section 57 of the shaft to rotate backward without rotating the section 57 backward. Fastcncd to the section 57 of the cam shaft is a can 70, the acting surface whereof is in the form of a spiral, thus forming a snail cam. Cooperating with the cam is an arm 71 pivoted upon a stationary fulcrum pin 72. The arm has a lug 74 on its underside which rests upon the cam with the result that as the cam rotates the arm 71 gradually rises and then suddenly falls. Riding upon the back or upper surface of the arm is a block 76 having a knife edge 7 for contacting the arm. The block is guided in a slot 80 arranged horizontally in the forward extension P51 of the arm 36 of the'rocking frame. A screw 82, shown in side elevation in Fig.

2. controls the position of the rider block lengthwise of the extension and thus controls the amount of throw of the rocking frame. By shifting the block away from pin 72 the throw will be increased and vice versa. As a result of this construction in which an intermediate arm 71 is interposed between the cam and the rocking frame, the movement produced by the cam may be magnified or diminished.

A helical compression spring 88 rests upon the bed 1 and supports a jack screw 89 screwing vertically in the lug 90 formed at the rear end of the rear extension 91 of the rocking plane. This serves to keep the rider block 76 in close contact with arm 71, and the latter in close contact with the cam 70.

In operation, when a hob is to be ground, the parts are assembled and adjusted as tating cam,

shown in the drawings and the machine is started. The driving belt 18 causes the grinding wheel to rotate at high speed, while the belt 55 causes the work spindle 24 to rotate and simultaneously feed the hob forward in an axial direction. The cam is also caused to rotate, which produces an oscillatory movement in the rocking frame and moves the hob gradually toward and suddenly awa from the wheel axis. This conforms to the relief in the hob teeth and it will be understood that the parts are so geared that the cam will rotate as many times faster than the hob as there are teeth in a com lete circumference of the hob. The grin 1n wheel not only rotates in a directlon to t row the sparks downward, but the wheel itself is located at the back of the machine-or at least on the side of the hob away from the operator. Consequently, the operator may lean over toward the work without danger of coming into contact with the fast rotating rinding wheel. Furthermore, as the spar s are thrown downward there is no danger of their being thrown into the operators eyes when he leans over to inspect the work. In addition, gravity assists in collecting the resulting dust and grit in an exhaust duct (not shown) which may be provided for conveying the same away from the machine.

After the wheel has ground one side of all of the hob teeth, the belt 18 is thrown oil the sheave 16, whereupon the tool carrying frame 5 may be turned over about its horizontal axis 6 thus causin the acting surface of the tool to present the proper anle' to rind the o posite side of the teeth.

he ho is brougll t back to starting position again, with the grinding wheel engaging the opposite side of the hob teeth, whereupon the action maybe repeated and the grindin finished.

It wil be noted that the sheave or pulley 16 is so located in the tool carrier that the on side (shown at the right in Fi 3) is substantially in line with the axis 0% the pivot which connects the tool carrier to the tool. The advantage in this is that it enables the tool carrier to be turned over to reverse position without disturbing the relation of the sheave o: pulley to the belt. In other words, the belt will run on to the pillley as well with the tool carrier in one position as it will with it in the reverse position.

Having thus described the invention what we claim as new and desire to secure by Letters Patent, is

1. A machine toolhaving a tool holder and a rockin frame,'one of which oscillates about afixefi axis for producing relative movement between the tool and the work for producin relief in the work, means for rotating th work in the work holder, a roa pivoted arm actuated by said .the axis of the tool a tool spindle journaled cam, a rider carried by the aforesaid part which oscillates, for transmlttin the movement of the arm to the part whic oscillates, said rider being adjustable relatively to the axis of the art whlch oscillates.

2. A macliine tool having a rocking frame for swinging the work toward and from the tool for taklng an eccentric cut, a cam for oscillating the rocking frame, a pivotally supported arm adapted to be oscillated about its pivot by said cam, and a rider directly cooperating with the arm and the rocking frame for transmitting the oscillatory movement of the arm to the rocking frame, said rider being adjustable towarand from the axis of one of the elements with which it directly cooperates.

3. A machine tool having a work holder, a tool holder adapted to resent a tool to the work, and a su port in w ich the tool holder is "ournaled, t e projected axis of the tool ho der in its su port passing approximately through the point of ap )lication of the tool to the work whereby t e tool may he reversed and present its face at a similar angle in the opposite direction.

machine tool having a tool post, a tool holder at an oblique angle to the axis of the work, a spindle journaled in the tool holder and adapted to rotate the tool, the tool holder being pivoted to the post and adapted to swing bout an axis lying approximately in a plane containing the axis of the spindle whereby the position of the tool carrier relatively to the work may be reversed to, thereby reverse the angle presented by the tool to the work.

5. A hob grinder having a. tool post, a tool carrier, a spindle journaled in said tool carrier and adapted to carry the grinding wheel, and a work spindle for supporting and rotating the bob, the tool carrier holding spindle at an oblique angle to the hob axis, and the tool carrier being pivoted to the toorpost upon an axis oblique to the axis of the tool spiridleg;

6. A machine tool having a tool carrier? in said carrier 3, pulle for driving the tool spindle, a slide slida ly mounted upon the tool carrier, 2. drive pulley journaled upon said slide, a belt for transmitting the motion of the drive pulley to the first mentioned pulley, and a spring for yieldingly forcing the pulleys apart to thereby keep the belt tight.

7. A machine tool having a tool 0st, 9. tool carrier pivoted to said post w ereby the tool carrier is reversible, a tool spindle journaled in the tool carrier, and a pulley mounted upon the tool carrier and connected to the tool spindle for rotatingit, the on, side of the pulley being substantially in line with the axis of the pivot connection be tween the tool carrier and the tool post.

8. A hob grinder having a tool carrier, a

tool spindle journaled in said carrier for rotating the grinding wheel, a work spindle for supportin the hob, means for rotat ng the hob spind e and simultaneously causing it to advance axially, a rocking frame wherein said work s indl is journaled, and a rotating earn a apted to rock the frame a plurality of times for every single rotation of the work spindle about its axis.

9. A hob grinder having a tool carrier, a tool spindle journaled in said carrier for rotating the grinding wheel, a work spindle for supporting the hob, means for rotating the hoh spindle and simultaneously causing it to advance axially, a rocking frame wherein said work spindle is journaled, and a snail cam acting upon the rookin frame for moving the hob gradually towart the grind ing wheel and suddenly away from it, the revolutions of the cam per minute being a multiple of the revolutions 'of the work spindle per minute.

10. A hob grinder having for rotating the hob, a rocking in said spindle is journaled, a

a work spindle frame wheretool carrier located at the rear of the frame, and cammechanism in front of the tool spindle for rocking said frame to thereby move the work toward and from the tool.

11. A relieving hob grinder having a tatable work spindle adapted to rarr the hob, a post, a frame journaled in sai post about an axis which, if extended or produced, will approximately pass through the timed relation with the speed of rotation for periodically reciproof the work spindle and from the axis eating said frame toward of the work spindle.

12. A hob grinder having for rotating the hob, a post, the post and the hob having a uniform relative motion parallel to the axis of the work spindle, a disk-like rinder, a grinder spindle adapted to hold the side of the grinder in contact with the side of the hob teeth, the point of contact of the grinder with the hob teeth lying approximately in the same plane with the axis of the work spindle and the axis of the grinding spindle, a frame in which the grinder spindle is journaled, a post upon \vhirh said frame is pivotally sup orted, the axis of the frame lying approximately in the same plane as the axis of the work spindie and the axis of the grinder spindle, and

driving means for said spindle carried by' the frame and rotatable with it.

In witness whereof, we have hereunto subscribed our names.

CARL (l. OLSON. FRANK W. ENGLAND.

a work spindle" DISCLAIMER- l,3S3,843.-0ar? 0. Olson and Frank W. Iz'wy la-nrl, Chicago, Ill. Hon-(hummus MACHINE. Patent dated July 5, 1921. Disclaimer filur] December 10, 1923, by the assignee, Illinois Tool Works.

Hereby enters this disclaimer To that part of the claim in said smw-iliw timl which is in the following words, to wit:

1. A machine tool having a tnni lilllillJ' and a rocking frame, one of which oscillates about a fixed axis for producing l'nhitiw movelm nt iwtwm-n the tool and the work for producing l'l'liflf in the \vurk, mum: fo'r rntut'ing the work in the work holder, :1 rntat-in cum, :1 zivnu-ii n rm m-tmltml by said cum, a l'iiili' ran-i011 by tho aforesaid part w ir'h nst'i laws. for transmitting the muvvnmnt of the arm to Hm part \vhir'h ask-Hiatus. mid l'ilil'l' {wing adjustable rvintivoiy tn tho axis of the part whicir pm'illatm;

2.':\ murrllinu tun] Inivifig a I'm-king frzumfor wringing In work toward and from t lu- 00! for taking an m'vnt-rir rut. a ram fur Ufiflihltillg the rocking frame, a pirninliy su ipurted arm ulla ltml tn lnufivilbrtmi almul; its iivut by said cam. and a ririor dirortl the oscillator,- movemunt 0f the arm to the rurking frame, said rider being mljustabie toward and from time axis of ono of the elements with which it ilirertly (ddjiura i I y vunpurating wlth the arm and tho Inc-king ramv for transmitting.

D SC L Al M E R 1,383',843.('m-l G. Olson. and Frank W Ear land, Chicago, Ill Hon-Gammxo Mxemxi-z. Patent dated July 1921. Disclaimer filed Deermber 12. 1924, by the assignee, Illinois T001 ll'orks. Hereby enters this disclai1ner- To that'part of the claim in the said specification which is in the following words, to wit:

3: A machine tool having a work holder, a tool holder adapted to present a tool to the work, and a support in which the tool holder is 'ournaled, the projected axis of the tool holder in its support passing approximate y through the point of application of the tool to the work whereby the tool may be reversed and present its face at a similar angle in the opposite direction.

'4. A machine tool having a tool post, a tool holder at an oblique angle to the axis of the work, a'spindle journaled in the tool holder and adapted to rotate the tool, the tool holder being pivoted to the post and adapted to swing: about an axis lying approximately in a plane containing the axis of the spindle whereby the position of the tool carrier relatively to the work may be reversed to therelr reverse the angle'presented by the tool to the work.

5: A hob grinder having a tool post, a tool carrier, a spindle journaled in said tool carrier and adapted to carry the grinding Wheel, and a work spindle for sup porting and rotating the hob. the tool carrier holding the axis of the tool Spindle at an oblique angle to the hub axis, and the tool carrier being pivoted to the tool post upon an axis oblique to the axis of the tool spindle.

" 11. A relieving hob grinder having a rotatable work spindle adapted to carry the..hob, a post, a frame journaled in said post about an axis which. if extended or produced, will approximately pass through the axisof the work spindle. a grinder spindle journaled in said frame and adapted to hold the grinder in eontaet with the hob at a point approximately in line with the axis of rotation of the frame. means for producing relative travel between the post and the work spindle in a direction parallel to the axis of the work spindle, and means operating in timed relation with the speed of rotation of the work spindle for periodically It!(l|1r0l':|ling said frame toward and from the axis of the work spindle.

12. A hob grinder having a work spindle for rotating the holi. a post. the post and the hob-hating a uniform relative motion parallel to the axis: of (he won spindle, a disk like grinder a grinder spindle adapted to hold the side of tingrinder in contact with the Hide of the hot teeth. the point of eontart of the grinder with the hob teeth lying: approximately in the same plane with the axis ol the \HHlt spihdle and the axis of the grinding spindle. a frame in which the grinder spindle is journaled, a post upon whirh said frame is pivotally supported. the axis ol' the frame lying approximately in the same plane as the axis of the work spindle and the axis of the grinder spindle. and driving means for said spindle carried by the frame, and rotatable with it.

[(Ifli ciaZ Gazette Del-Mabel Fill. 1.92.4.1 

